SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48bd518702e4dae3601746e61484603e85ea91daf9974a4d04be97311944ad76' 
  AND token = 'ckYZLJPPh4APlxDkDKURcfciZH4TxLleS5PI6aqGjzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}